The scheduled publishing mechanism adds an expired field to wagtailcore.Page, defaulting to False. Any application code working with Page objects should be unaffected, but any code that creates page records using direct SQL, or within existing South migrations using South’s frozen ORM, will fail as this code will be unaware of the expired database column. To fix a South migration that fails in this way, add the following line to the 'wagtailcore.page' entry at the bottom of the migration file:

Previously, the route method called serve and returned an HttpResponse object. This has now been split up so serve is called separately and route must now return a RouteResult object.

If you are overriding Page.route on any of your page models, you will need to update the method to return a RouteResult object. The old method of returning an HttpResponse will continue to work, but this will throw a DeprecationWarning and bypass the before_serve_page hook, which means in particular that Private pages will not work on those page types. See Adding Endpoints with Custom route() Methods.